Ground Water Modelling for the Restoration of Carex Communities on a Sandy River Terrace

Abstract

Management for sustainable river valleys requires balancing their natural values against the need for agricultural and recreational development on surrounding lands. The Southern Całowanie Peatland near the city of Warsaw sits on a sandy terrace and has well preserved Carex and Molinia stands existing in part of the area, especially where water tables are less than 1.5 m below the surface. The existing drainage network in this southern part has been poorly maintained and could be reestablished to help raise water levels for restoration of the peatland. Modflow was used to look at influence of drainage channel water levels on the overall water table height in the area. By raising water levels in the drainage system by 0.5 m it was found that 29% of the area would become suitable for increasing Carex and Molinia communities.

Sustainable management of different valley ecosystems

“…2.). Still, the presence of wetland plant species there suggests that the drainage did not cause their considerable deterioration over last decades [7]. One of the most important hydrologic features of that system is the underlying, thick 10 m, sandy aquifer of a high permeability from the viewpoint of sustainable ground water resources management and overall ecosystem health.…”

“…In the next stage of analyses, the validation of the models was performed with the use of prior hydrologic information and literature data [7,9]. The aim was to prove the reliability of the models to reproduce the ground water table position with the assumed set of parameters.…”

“…The stage of model validation was followed by the adoption of criteria to provide for managers' role in the maintenance of a certain environmental status of the analysed areas. It has been still the subject of controversy, and usually requires expert brainstorming, as a wide range of criteria or indicators is too relative [7,9]. Many of them may be attributed to a general socio-economical and also environmental descriptive view of valley ecosystems.…”

“…From a variety of available evaluation criteria we distinguished the change in groundwater storage within the areas as the first, analysed indicator. The second one was the required groundwater table position, resulting from the prospective soil moisture complex [7,9,10] which is more a hydrological indicator, having also reference to the description of land production potential, but also nature status versus water regime.…”

“…Nonetheless, the amount of groundwater coming in and out of the systems was obtained for each month of the year, and the allowable water level decline was as well adopted. For the latter, we used the existing design experience, that divided the soils into moisture categories, so the first research area was assigned the maximum depth to water table of 0,70 m. and the second one equal to 0,85 m. The depth reflected the expected soil properties and targeted area wetness [7,9]. Fig.…”